Underlying event activity in p+p 200 GeV with Mono jet for Jet Patch trigger-- 2015-10-07

Updated on Fri, 2015-10-09 14:05. Originally created by yili on 2015-10-07 10:55.

Motivation:

Followed the study on drupal.star.bnl.gov/STAR/blog/yili/underlying-event-activity-pp-200-gev-2015-09-28-2 (R=0.4, Dijet required, HIgh Tower trigger)

also drupal.star.bnl.gov/STAR/blog/yili/underlying-event-activity-pp-200-gev-mono-jet-2015-10-02-0 (R = 0.6, at least one jet, High Tower trigger)

Here R = 0.6, at least one jet, Jet patch trigger

How does underlying event multiplicity, average pT change with Leadiing jet pT?

CMS publication: arxiv.org/abs/1507.07229

CDF publication: arxiv.org/abs/1508.05340

Grant Webb's study on p+p 500 GeV data: drupal.star.bnl.gov/STAR/blog/gdwebb/underlying-event-run-9-pp-500-gev
Zilong Change's study on PYTHIA p+p 500 GeV: drupal.star.bnl.gov/STAR/blog/zchang/underlying-event-study-4

Here is Li Yi's third step to study the underlying event in p+p 200 GeV.

See Master Page: drupal.star.bnl.gov/STAR/blog/yili/master-page-underlying-event-pp-200-gev

Data:

p+p 200 GeV
Run 12
filetype=daq_reco_MuDst,events!=0,trgsetupname=pp200_production_2012,filename~st_physics,production=P13ib,storage!=hpss,sanity=1

triggerid: 370601, 370611, 370621
for JP0, JP1, JP2

Cuts:

|Vz|<30 cm
|eta|<1
|dca|< 1 cm
NFIt > 20 points
NFit/NFitPossible > 0.52
Track Pt or Tower Et<1000GeV

no pileup removal

anti-kT algorithm
R = 0.6
ghost area 0.01

14M events, found 2.3 M jet events (no jet pT requirement)

Method:

1. Search for jet, identify jet φ_jet
Both TPC tracks and BEMC towers are used for jet reconstruction by fastjet pacakge.

2. Loop over tracks (charged particles only)

For the two transverse directions, the one with larger pT sum of the charged particle is defined as TranMax. The other is TranMin.

3. Sum the multiplciity in various directions.
Calucate the average pT in various directions.

Result:

The results from combined JP0+JP1+JP2 triggers (colume 1) and JP2 trigger (column 2) only are compared.

1. Leading jet Pt Distribution:

2. Ntrk in Leading Jet Direction vs Leading Jet Pt
(number of charged particles in |φ-φ_jet|<60 degree, including the particles belongs to leading jet) :

Here we can see that the trigger effect of JP2 shows a little bump at pt 5-10 GeV/c.

3. Sum of charged particle pT in Leading Jet Direction vs Leading Jet Pt. The title in the plot was wrong: it is sum not mean <pT>.
(in |φ-φ_jet|<60 degree, including the particles belongs to leading jet) :

4. charged particle pT distribution in Leading Jet Direction vs Leading Jet Pt
(in |φ-φ_jet|<60 degree, including the particles belongs to leading jet) :

5. Ntrk in recoil side of Jet Direction vs Leading Jet Pt
(number of charged particles in |φ-φ_dijet|>120 degree, does not requiring subleading existence ):

6. Sum of particle pT in recoil side of Jet Direction vs Leading Jet Pt. The title in the plot was wrong: it is sum not mean <pT>.
(number of charged particles in |φ-φ_dijet|>120 degree, does not requiring subleading existence ):

6. Charged particle pT distribution in recoil side of Jet Direction vs Leading Jet Pt
(number of charged particles in |φ-φ_dijet|>120 degree, does not requiring subleading existence ):